1. Field of the Invention
The present invention relates to a generator cooling system of an engine forcibly cooling a generator with oil.
2. Prior Art
A generator of an engine is generally structured by arranging a rotor and a stator coil in a generator room, and is generally structured such as to be cooled for preventing a power generation efficiency from being lowered, because the generator generates heat during operation of the engine. As cooling systems, there are an air cooling type and a fluid cooling type. However, the fluid cooling type utilizing oil provides a better cooling effect. Particularly, in the case that a rotor is directly coupled to a crankshaft of the engine and the generator room is sealed by a generator cover, there is employed a forcible cooling structure using oil.
As a conventional oil type generator cooling system, there is a system described in Japanese Patent No. 2898257. FIG. 6 shows a generator cooling system described in the publication mentioned above, in which a generator room 104 is formed by fastening a generator cover 102 to a side wall in an axial length direction of a crankshaft 103 of a crankcase 101, and a generator is accommodated in the generator room 104. The generator is constituted by a rotor 106 fixed to an end portion of the crankshaft 103, and a stator coil 110 fixed to an inner surface of the generator cover 102. An oil nozzle 111 for cooling the generator is formed at an end portion of an oil passage 112 formed within a wall of the crankcase 101, and is arranged at position higher than an axis O1 of the crankshaft 103 and at approximately an upper end position of the generator room 104.
In accordance with the structure in FIG. 6, the oil injected into an upper end portion of the generator room 104 from the oil nozzle 111 goes around an outer portion in a radial direction of an outer peripheral wall 106c of the rotor 106 on the basis of a rotation of the rotor 106, and is sequentially scattered to the stator coil 110 in the middle of going around.